How Does VoIP Affect the Network?

How does voice-over Internet protocol (VoIP) affect networks? In a word, it makes them better — because it has to. Routing the human voice over LANs and WANs is harder and more turbulent than routing data from e-mail, ERM or CRP. Even the smallest flaws in a network that bears the burden of data traffic without a sigh or a grunt can make a VoIP call sound as if someone is speaking in tongues, and that, in turn, makes network administrators, engineers and IT managers shore up their networks like never before.

Three for the Road

The famous triad of VoIP problems, of course, is latency, jitter and packet loss. Latency is the time it takes for a word to move from the mouth of the person speaking it to the ear of the person listening. The higher the latency, the longer it takes for something you say to make its way over the network, meaning the person you’re speaking to will hear it one, two or even three seconds after you say it. And no user will stand for that, from the sweetest receptionist to the most tight-fisted CEO.

Jitter is a variation in latency. If a set of voice packets makes its way to its destination faster than others, the normal, smooth stream of voice is fractured like a glass falling on cement. And packet loss, of course, is simply the loss of data itself, meaning that parts of a word or a whole sentence will be removed from a conversation.

Get Ready to Upgrade

Installing VoIP can be fairly described as the process of fighting latency, jitter and packet loss. When firms move to VoIP to save money on their long-distance bills, to enjoy high-end calling features or to let employees work from home seamlessly, they first assess their networks to ensure the added bandwidth of voice traffic won’t grind business to a halt.

Properly done, the assessment is thorough, to say the least. Weeks and months of traffic is analyzed with packet sniffers and probes to search for peak points, patterns and the effects of spikes in existing data traffic across routers, switches and known bottlenecks.

PBX logs are vetted to see when people call the most and how long they talk, and future projects, including large-scale software deployments and client-server applications that could stress an already over-taxed network, get factored into the mix too.

The bottom line? Most companies upgrade their networks before they roll out VoIP, adding smart switches that can route traffic intelligently or software that can manage and prioritize voice packets over data, ensuring key quality of service (QoS) metrics are met or even surpassed.

They look to dual-core switching or well-designed VLANs to segment traffic for maximum uptime. And they upgrade their power supplies, spending extra dollars on UPS systems that will keep key servers and VoIP phones online in case of a brownout.

Why all the fuss? Consider this: E-mail can freak out for a few seconds — or even a few minutes — without much complaint. But apart from a pen or pencil, the phone is perhaps the oldest of the major business tools, and one that’s been tested, retested and hardened for the last 100 years.

Users who like to complain about the smallest IT glitch will scream to the rafters if their phones go silent, meaning that VoIP — and the networks that use it — need to be perfect out of the gate.